Improvement in the manufacture of oxede of zinc from sulphuretted ores



D. LEES.

Making Oxide of Zinc. No. 83,643. Patented Nov. 3,1868.

Witnesse s3 Irw ewto r.-

N. PETERS, Photo-Lithographer. Washington, D, C.

a To allure ham it may concern;

Be it known that I, DAVID Lens, of 'Blair county,

i tiniiml finite;

DAVID LEE S, OF BLAIR COUNTY, PENNSYLVANIA.

Letters Patent No; 83,643, dated November 3, 1868.

IMPROVEMENT IN THE MANUFACTURE or oxrnn or znvt; rRoM SULPHURE'ITED onus.

I The Schedule referred to in these Letters Patent and making part of the same. I

in the State of Pennsylvania, have invented an Improvement in the Art or Manufacture 'of Oxide of Zinc, or of a mixture of oxide of zinc and sulphate of lead'from ores of sulphuret of zinc, or from sulphuret ofzinc containing galena, or sulphuret. of lead, by the introduction of a current or blast of air into the ordinary oxide-of-zinc, or other furnaces, in such a manner that there shallbe maintained-a constant oxidizing atmosphere above the whole surface of the bath 'or charge of mixed ore and coal; and I do hereby declare that the following is a full and exact description thereof,

reference being had to theaccompanying drawings, and to the letters of reierencenrarked thereon.

The nature of my invention consists in the applica tion of a blast or current of air by means of a supplypipe, a, with slots 0 o, enclosed in pipe 12, kept constantly filled with water, which water is kept hot by the fire of the furnace, and, whilst it heats the air introduced, prevents the destruction of the pipes, The pipe at is also furnished with valves d d, for regulating the supply of air which is thereby introduced above the charge, and distributed perfectly over the whole interiorsurface 01' the furnace, so as to maintain a constant oxidizing-atmosphere.

By thus applying a hot blastsubstantially in the manner described, threefold advantages are secured:

First, by introducing the air above the charge of ore and fuel, there is maintained an atmosphere which is always oxidizing, whereas, if the air has access frdm beneath, it becomes mixed with reducing-gases, such as carbonic oxide, resulting from the imperfect combustion of the fuel, 860. These reducing-gases -act injuriously, by preventing the oxidation of sulphuret or sulphide of lead, which is of a dark color, and its conversion into sulphate of the oxide .of lead, which is white. In an oxidizing-atmosphere such as I produce,

' this chemical change is perfectly efi'ected, and the sulphate of lead is forced over into the ordinary collectingapparatus, along with the oxide of zinc, by means of the blast or current.

Second, there being a perfect oxidation of the prodnets of the heated mixture of ore and coal, there can be no volatile hydrocarbons and free carbon in a state of minute division carried over with the produced oxicle. These would impair the color of the oxide of zinc. By this means bituminous coals can be employed to mix with the ore, instead of only anthracite, as in the ordinary methods. v

Third, by distributing this blast over the whole interior surface of the furnace, which is perfectly done only by the above-described arrangement, the oxide of zinc and sulphate of lead are producedinanatmosphere with a temperature suflicientl'y elevated to decompose all the suiphate of zinc, which is always formed and exists in oxide of zinc, when manufactured from sulphuretted ores in the previously-employed methods. This sulphate of zinc, although white, is of a'crystalline nature, and will not admit of being mixed with oil, so as to produce a homogeneous mixture, free from small lumps or granules, adapted to the purposes of an oilpigment. 7

What I claim as my invention, and desire to secure by Letters Patent, is-- The application of a hot blast, substantially in the manner and by the process above described, to the manufacture of oxide of zinc, whereby the oxide is always formed in an oxidizing-atmosphere, and at a temperature sufficiently elevated to decompose all in jurious products.

DAVID LEES.

Witnesses:

W. L. GALDERWOOD, J. P. STEWART. 

